Not even on a full sized full frame DSLR is f/11 the sweet spot -- by that point diffraction will be reducing recorded resolution. I find that with my full frame DSLR's the sweet spot is more like f/6.3-f/8 but can be a lower f/# if the scene permits it. So, if I'm shooting from a high vantage point that has no close object in the FOV you are better off using more like f/4 or so for a couple reasons. First, at f/4 there is very little diffraction limiting and a faster shutter speed helps to reduce blurring due to subject or camera motion.
Here's a test you can do that will confirm what I say. Set you camera up on a tripod and take pictures in aperture priority mode of the same scene at f/4, f/5.6, f/6.3, f/7.1, f/8, f/9, f/10, f/11 and f/13. Then look at the file size for each image -- I think you'll see that your maximum file size will tend to be around f/6.3 to f/8 with f/7.1 often the max. What's happening here is that the raw image is being lossless compressed and the file size is larger when there is more recorded detail. A high f/# will increase DOF but at the cost of diffraction, a lower f/# will have less diffraction blurring but at the cost os lower DOF. In the middle is the sweet spot most of the time. But, if you can frame the shot without close object or if everything is at nearly the same distance than that moves the sweet spot to a lower f/# -- even down below f/4 under some circumstances. OTH, if you have a shot that has huge differences in DOF and you want as much in decent focus as possible than go ahead and shoot at f/11 or even higher. Just know that your image will not be recorded at full resolution -- physics won't permit it.
With the smaller sensors on the
P4P and similar drones the sweet spot will be a lower f/#. For the
P4P I'd put the sweet spot at more like f/4 to f/7.1.
Brian